Agile Validation of Higher Order Transformations Using F-Alloy

Model transformations play a key role in model driven software engineering approaches. Validation of model transformations is crucial for the quality assurance of software systems to be constructed. The relational logic based specification language Alloy and its accompanying tool the Alloy Analyzer have been used in the past to validate properties of model transformations. However Alloy based analysis of transformations suffers from time complexity and scalability issues. The problem becomes even more severe when it comes to higher order transformations that are inherently more complex. In previous work, we proposed a sub-language of Alloy, called F-Alloy, that is tailored for model transformation specifications. Instead of pure analysis based validation, F-Alloy speeds up the validation of model transformations by applying a hybrid strategy that combines analysis with interpretation. In this paper, we show how the F-Alloy approach can be extended to also support efficient validation of higher order transformations

Agile Validation of Model Transformations using Compound F-Alloy Specifications

Model transformations play a key role in model driven software engineering approaches. Validation of model transformations is crucial for the quality assurance of software systems to be constructed. The relational logic based specification language Alloy and its accompanying tool the Alloy Analyzer have been used in the past to validate properties of model transformations. However Alloy based analysis of transformations suffers from several limitations. On one hand, it is time consuming and does not scale well. On the other hand, the reliance on Alloy, being a formal method, prevents the effective involvement of domain experts in the validation process which is crucial for pinpointing domain pertinent errors. Those limitations are even more severe when it comes to transformations whose input and/or output are themselves transformations (called compound transformations) because they are inherently more complex. To tackle the performance and scalability limitations, in previous work, we proposed an Alloy-based Domain Specific Language (DSL), called F-Alloy, that is tailored for model transformation specifications. Instead of pure analysis based validation, F-Alloy speeds up the validation of model transformations by applying a hybrid strategy that combines analysis with interpretation. In this paper, we formalize the notion of “hybrid analysis” and further extended it to also support efficient validation of compound transformations. To enable the effective involvement of domain experts in the validation process, we propose in this paper a new approach to model transformation validation, called Visualization-Based Validation (briefly VBV). Following VBV, representative instances of a to-be-validated model transformation are automatically generated by hybrid analysis and shown to domain experts for feedback in a visual notation that they are familiar with. We prescribe a process to guide the application of VBV to model transformations and illustrate it with a benchmark model transformation

On the Use of Alloy in Engineering Domain Specific Modeling Languages

Domain Specific Modeling Languages (DSMLs) tend to play a central role in modern design processes as they enable the effective involvement of domain experts by focusing on a particular problem domain while abstracting away technical details. In this thesis, we investigate the specification of DSMLs with a particular focus on domain expert driven validation. Mainly, we are interested in developing Alloy-based approaches, allowing the definition of specifications from which instances can be generated and given to the domain experts for the sake of validation. The work we present in this thesis can be divided into three parts: The first part concerns the definition and execution of model transformations defined in Alloy. While Alloy analysis can be used as an execution engine for model transformations, the analysis process is time consuming. Model transformations playing a central role in DSML definitions, the development of a new model transformation language, named F-Alloy, retaining the benefits of Alloy with the added property of being efficiently computable was necessary. The second part focuses on validation. In that domain, our first contribution is a novel approach to the validation of model transformations called Visualization-Based Validation (VBV). VBV relies on the review by domain experts of intuitive depictions of model transformation traces to validate model transformation specifications. The whole process is made efficient by the usage of hybrid analysis, a combination of Alloy analysis and F-Alloy interpretation, allowing to reduce the time needed to analyze model transformations to the time needed to analyze its source. Our second contribution in the validation area is the definition of an Alloy-based approach to the specification and validation of DSMLs and of a design process defining how DSMLs can be validated using Alloy analysis at each iteration of the process. More precisely, we present how the abstract syntax, concrete syntax and operational semantics of a DSML can be defined using Alloy and F-Alloy, and show that the validation of a DSML' s abstract syntax and semantics benefits from the application of its concrete syntax. The third and last part aims at bringing those contributions to the practical world. To achieve this we developed a tool named Lightning implementing the aforementioned contributions. This tool, which belongs to the category of language workbenches, has been successfully used in an inter-disciplinary collaboration to define the Robot Perception System Language (RPSL). Based on this definition of RPSL, a framework has been developed to allow the execution of so called design space explorations. This framework represents a successful application of our approach to the real world problem of having RPSL specifications validated by experts in robotics